When an application needs to access a file, it must first open it using fs_fopen() or FSFile_Open(). For most applications, the former with its familiar interface suffices. In some cases, the flexibility of the latter is demanded (see Listing - Example FSFile_Open() usage).
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| Listing - Example FSFile_Open() usage |
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| Listing - Example FSFile_Open() usage |
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| Code Block |
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| language | cpp |
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| title | Listing - Example FSFile_Open() usage |
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file ptr --> p_file = FSFile_Open ("\\file.txt", /* file name */
FS_FILE_ACCESS_MODE_RD, /* access mode */
&err); /* return error */
if (p_file == (FS_FILE *)0) {
/* $$$$ Handle error */
} |
The return value of FSFile_Open() should always be verified as non-NULL before the application proceeds to access the file. The second argument to this function is a logical OR of mode flags:
...
It is impossible to do this in a single, atomic operation using fs_fopen().
The table below lists Table - fopen() mode strings and mode equivalents lists the mode flag equivalents of the fs_fopen() mode strings.
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| borderWidth | 0 |
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| title | Table - fopen() mode strings and mode equivalents |
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“r” or “rb”
| FS_FILE_ACCESS_MODE_RD
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“w” or “wb”
| FS_FILE_ACCESS_MODE_WR
FS_FILE_ACCESS_MODE_CREATE
FS_FILE_ACCESS_MODE_TRUNC
| “a” or “ab”
| FS_FILE_ACCESS_MODE_WR
FS_FILE_ACCESS_MODE_CREATE
FS_FILE_ACCESS_MODE_APPEND
| “r+” or “rb+” or “r+b”
| FS_FILE_ACCESS_MODE_RD
FS_FILE_ACCESS_MODE_WR
| “w+” or “wb+” or “w+b”
| FS_FILE_ACCESS_MODE_RD
FS_FILE_ACCESS_MODE_WR
FS_FILE_ACCESS_MODE_CREATE FS_FILE_ACCESS_MODE_TRUNC
| “a+” or “ab+” or “a+b”
| FS_FILE_ACCESS_MODE_RD
FS_FILE_ACCESS_MODE_WR
FS_FILE_ACCESS_MODE_CREATE
FS_FILE_ACCESS_MODE_APPEND
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