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FreeRTOS+FAT is still in the lab
FreeRTOS+FAT is already in use in commercial products and we encourage you to try it yourself. Be aware however that FreeRTOS+FAT was acquired by Real Time Engineers Ltd., and is still being documented and updated to ensure it meets our strict quality standards. Please use the forum for support, or contact us directly if you have a specific business interest.

ff_findnext()

[FreeRTOS+FAT Standard API Reference]

ff_stdio.h 
int ff_findnext( FF_FindData_t *pxFindData );

Finds the next file or directory within an embedded FAT file system directory. ff_findnext() can only be called after first calling ff_findfirst(). ff_findfirst() finds the first file in the directory, ff_findnext() then finds all subsequent files in the directory.

The same instance of the FF_FindData_t object must be passed into ff_findnext() as was passed into ff_findfirst().

FF_FindData_t contains the fields shown in the table below:

Field
Description
pcFileName The name of the file
ulFileSize The length of the file in bytes
ucAttributes The file's attributes, which is a bitwise OR of the following bit definitions:
  • FF_FAT_ATTR_READONLY
  • FF_FAT_ATTR_HIDDEN
  • FF_FAT_ATTR_SYSTEM
  • FF_FAT_ATTR_DIR (directory)

Parameters:

pxFindData   A pointer to a structure that is used to store information required to scan a directory, and to pass out details of the files contained in the directory.
Returns:

If a file or directory was found then 0 is returned. If an error occurs a non-zero value is returned.

Example usage: 


void DIRCommand( const char *pcDirectoryToScan )
{
FF_FindData_t *pxFindStruct;
const char  *pcAttrib;
            *pcWritableFile = "writable file",
            *pcReadOnlyFile = "read only file",
            *pcDirectory = "directory";

    /* FF_FindData_t can be large, so it is best to allocate the structure
    dynamically, rather than declare it as a stack variable. */
    pxFindStruct = ( FF_FindData_t * ) pvPortMalloc( sizeof( FF_FindData_t ) );

    /* FF_FindData_t must be cleared to 0. */
    memset( pxFindStruct, 0x00, sizeof( FF_FindData_t ) );

    /* The first parameter to ff_findfist() is the directory being searched.  Do
    not add wildcards to the end of the directory name. */
    if( ff_findfirst( pcDirectoryToScan, pxFindStruct ) == 0 )
    {
        do
        {
            /* Point pcAttrib to a string that describes the file. */
            if( ( pxFindStruct->ucAttributes & FF_FAT_ATTR_DIR ) != 0 )
            {
                pcAttrib = pcDirectory;
            }
            else if( pxFindStruct->ucAttributes & FF_FAT_ATTR_READONLY )
            {
                pcAttrib = pcReadOnlyFile;
            }
            else
            {
                pcAttrib = pcWritableFile;
            }

            /* Print the files name, size, and attribute string. */
            FreeRTOS_printf( ( "%s [%s] [size=%d]", pxFindStruct->pcFileName,
                                                  pcAttrib,
                                                  pxFindStruct->ulFileSize ) );

        } while( ff_findnext( pxFindStruct ) == 0 );
    }

    /* Free the allocated FF_FindData_t structure. */
    vPortFree( pxFindStruct );
}
Example use of the ff_findfirst() API function create a directory listing



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