1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Internal Support for POSIX Shared Memory |
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5 | */ |
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6 | |
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7 | /* |
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8 | * Copyright (c) 2016 Gedare Bloom. |
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9 | * |
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10 | * The license and distribution terms for this file may be |
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11 | * found in the file LICENSE in this distribution or at |
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12 | * http://www.rtems.org/license/LICENSE. |
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13 | */ |
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14 | |
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15 | #ifndef _RTEMS_POSIX_SHM_H |
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16 | #define _RTEMS_POSIX_SHM_H |
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17 | |
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18 | #include <rtems/score/objectdata.h> |
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19 | #include <rtems/score/threadq.h> |
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20 | |
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21 | #include <sys/types.h> |
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22 | |
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23 | #ifdef __cplusplus |
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24 | extern "C" { |
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25 | #endif |
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26 | |
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27 | /** |
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28 | * @defgroup POSIXShmPrivate POSIX Shared Memory Private Support |
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29 | * |
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30 | * @ingroup POSIXAPI |
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31 | * |
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32 | * Internal implementation support for POSIX shared memory. |
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33 | * @{ |
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34 | */ |
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35 | typedef struct POSIX_Shm_Object_operations POSIX_Shm_Object_operations; |
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36 | extern const POSIX_Shm_Object_operations _POSIX_Shm_Object_operations; |
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37 | |
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38 | /** |
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39 | * @brief Encapsulation for the storage and manipulation of shm objects. |
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40 | */ |
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41 | typedef struct { |
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42 | /** |
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43 | * @brief The handle is private for finding object storage. |
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44 | */ |
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45 | void *handle; |
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46 | |
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47 | /** |
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48 | * @brief The number of bytes allocated to the object. A size of 0 with |
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49 | * a handle of NULL means no object is allocated. |
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50 | */ |
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51 | size_t size; |
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52 | |
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53 | /** |
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54 | * @brief Implementation-specific operations on shm objects. |
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55 | */ |
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56 | const POSIX_Shm_Object_operations *ops; |
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57 | } POSIX_Shm_Object; |
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58 | |
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59 | /** |
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60 | * @brief Operations on POSIX Shared Memory Objects. |
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61 | */ |
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62 | struct POSIX_Shm_Object_operations { |
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63 | /** |
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64 | * @brief Allocates a new @a shm_obj with initial @a size. |
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65 | * |
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66 | * New shared memory is initialized to zeroes. |
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67 | * |
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68 | * Returns 0 for success. |
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69 | */ |
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70 | int ( *object_create ) ( POSIX_Shm_Object *shm_obj, size_t size ); |
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71 | |
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72 | /** |
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73 | * @brief Changes the @a shm_obj size to @a size. |
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74 | * |
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75 | * Zeroes out the portion of the shared memory object that shrinks or grows. |
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76 | * |
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77 | * Returns 0 for success. |
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78 | */ |
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79 | int ( *object_resize ) ( POSIX_Shm_Object *shm_obj, size_t size ); |
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80 | |
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81 | /** |
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82 | * @brief Deletes the @a shm_obj. |
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83 | * |
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84 | * Zeroes out the memory. |
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85 | * |
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86 | * Returns 0 for success. |
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87 | */ |
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88 | int ( *object_delete ) ( POSIX_Shm_Object *shm_obj ); |
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89 | |
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90 | /** |
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91 | * @brief Copies up to @count bytes of the @a shm_obj data into @a buf. |
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92 | * |
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93 | * Returns the number of bytes read (copied) into @a buf. |
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94 | */ |
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95 | int ( *object_read ) ( POSIX_Shm_Object *shm_obj, void *buf, size_t count ); |
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96 | |
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97 | /** |
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98 | * @brief Maps a shared memory object. |
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99 | * |
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100 | * Establishes a memory mapping between the shared memory object and the |
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101 | * caller. |
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102 | * |
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103 | * Returns the mapped address of the object. |
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104 | */ |
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105 | void * ( *object_mmap ) ( POSIX_Shm_Object *shm_obj, size_t len, int prot, off_t off); |
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106 | }; |
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107 | |
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108 | /** |
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109 | * @brief Control for a POSIX Shared Memory Object |
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110 | */ |
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111 | typedef struct { |
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112 | Objects_Control Object; |
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113 | Thread_queue_Control Wait_queue; |
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114 | |
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115 | int reference_count; |
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116 | |
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117 | POSIX_Shm_Object shm_object; |
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118 | |
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119 | uid_t uid; |
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120 | gid_t gid; |
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121 | mode_t mode; |
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122 | int oflag; |
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123 | |
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124 | time_t atime; |
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125 | time_t mtime; |
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126 | time_t ctime; |
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127 | } POSIX_Shm_Control; |
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128 | |
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129 | /** |
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130 | * @brief The POSIX Shared Memory objects information. |
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131 | */ |
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132 | extern Objects_Information _POSIX_Shm_Information; |
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133 | |
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134 | /** |
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135 | * @brief Macro to define the objects information for the POSIX Shared Memory |
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136 | * objects. |
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137 | * |
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138 | * This macro should only be used by <rtems/confdefs.h>. |
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139 | * |
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140 | * @param max The configured object maximum (the OBJECTS_UNLIMITED_OBJECTS flag |
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141 | * may be set). |
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142 | */ |
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143 | #define POSIX_SHM_INFORMATION_DEFINE( max ) \ |
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144 | OBJECTS_INFORMATION_DEFINE( \ |
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145 | _POSIX_Shm, \ |
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146 | OBJECTS_POSIX_API, \ |
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147 | OBJECTS_POSIX_SHMS, \ |
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148 | POSIX_Shm_Control, \ |
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149 | max, \ |
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150 | _POSIX_PATH_MAX, \ |
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151 | NULL \ |
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152 | ) |
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153 | |
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154 | /** |
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155 | * @brief object_create operation for shm objects stored in RTEMS Workspace. |
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156 | */ |
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157 | extern int _POSIX_Shm_Object_create_from_workspace( |
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158 | POSIX_Shm_Object *shm_obj, |
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159 | size_t size |
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160 | ); |
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161 | |
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162 | /** |
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163 | * @brief object_delete operation for shm objects stored in RTEMS Workspace. |
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164 | */ |
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165 | extern int _POSIX_Shm_Object_delete_from_workspace( POSIX_Shm_Object *shm_obj ); |
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166 | |
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167 | /** |
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168 | * @brief object_resize operation for shm objects stored in RTEMS Workspace. |
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169 | */ |
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170 | extern int _POSIX_Shm_Object_resize_from_workspace( |
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171 | POSIX_Shm_Object *shm_obj, |
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172 | size_t size |
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173 | ); |
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174 | |
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175 | /** |
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176 | * @brief object_read operation for shm objects stored in RTEMS Workspace. |
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177 | */ |
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178 | extern int _POSIX_Shm_Object_read_from_workspace( |
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179 | POSIX_Shm_Object *shm_obj, |
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180 | void *buf, |
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181 | size_t count |
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182 | ); |
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183 | |
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184 | /** |
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185 | * @brief object_mmap operation for shm objects stored in RTEMS Workspace. |
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186 | */ |
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187 | extern void * _POSIX_Shm_Object_mmap_from_workspace( |
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188 | POSIX_Shm_Object *shm_obj, |
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189 | size_t len, |
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190 | int prot, |
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191 | off_t off |
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192 | ); |
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193 | |
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194 | /** |
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195 | * @brief object_create operation for shm objects stored in C program heap. |
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196 | */ |
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197 | extern int _POSIX_Shm_Object_create_from_heap( |
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198 | POSIX_Shm_Object *shm_obj, |
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199 | size_t size |
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200 | ); |
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201 | |
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202 | /** |
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203 | * @brief object_delete operation for shm objects stored in C program heap. |
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204 | */ |
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205 | extern int _POSIX_Shm_Object_delete_from_heap( POSIX_Shm_Object *shm_obj ); |
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206 | |
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207 | /** |
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208 | * @brief object_resize operation for shm objects stored in C program heap. |
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209 | */ |
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210 | extern int _POSIX_Shm_Object_resize_from_heap( |
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211 | POSIX_Shm_Object *shm_obj, |
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212 | size_t size |
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213 | ); |
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214 | |
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215 | /** |
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216 | * @brief object_read operation for shm objects stored in C program heap. |
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217 | */ |
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218 | extern int _POSIX_Shm_Object_read_from_heap( |
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219 | POSIX_Shm_Object *shm_obj, |
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220 | void *buf, |
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221 | size_t count |
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222 | ); |
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223 | |
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224 | /** |
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225 | * @brief object_mmap operation for shm objects stored in C program heap. |
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226 | */ |
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227 | extern void * _POSIX_Shm_Object_mmap_from_heap( |
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228 | POSIX_Shm_Object *shm_obj, |
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229 | size_t len, |
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230 | int prot, |
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231 | off_t off |
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232 | ); |
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233 | |
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234 | /** @} */ |
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235 | |
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236 | #ifdef __cplusplus |
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237 | } |
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238 | #endif |
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239 | |
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240 | #endif |
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