This function will be called during file operations when a SEEK is required.
Declaration:
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typedef AT_INT(ACCUAPI LPFNIG_SEEK) (
AT_INT fd,
AT_INT lOffset,
INT nFlag
);
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Arguments:
| Name | Type | Description |
| fd | AT_INT | File Descriptor handle. |
| lOffset | AT_INT | Offset to which to seek. |
| nFlag | INT | 0 = seek from start; 1 = seek from current position; 2 = seek from end. |
Return Value:
Return offset into file at the completion of the seek, or -1 to indicate an error occurred.
Supported Raster Image Formats:
This function does not process image pixels.
Sample:
IOSET
Example:
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HIGEAR hIGear; /* HIGEAR handle of image */ LPFNIG_READ MyReadFunc; /* To be called for READs */ LPFNIG_WRITE MyWriteFunc; /* To be called for WRITEs */ LPFNIG_SEEK MySeekFunc; /* To be called for SEEKs */ { /* Register Read, Write, and Seek callback functions: */ IG_file_IO_register ( MyReadFunc, MyWriteFunc, MySeekFunc ); ... IG_save_file ( hIGear, "picture.bmp", IG_SAVE_BMP_UNCOMP ); ... } /* This will be called for each seek during the above Save: */ LONG ACCUAPI MySeekFunc ( AT_INT fd, AT_INT lOffset, INT nFlag ) { AT_INT nResultOffset; ... return nResultOffset; } |
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Remarks:
This type of function is established by calling IG_file_IO_register(). This function should return the offset into the file after the seek has completed, or -1 to indicate that an error occurred.