ff_errno()

[FreeRTOS+FAT Standard API Reference]

ff_stdio.h

int ff_errno( void );
		

File related functions in the standard C library often return 0 for pass, and -1 for fail. If -1 is returned then the reason for the failure is stored in a variable called errno, which must be inspected separately.

FreeRTOS+FAT's standard stdio style interface maintains an errno variable for each RTOS task. ff_errno() returns the errno value for the calling task.

Notes:

• The file system's C library style API uses the same errno values as used by the stanard C library. These are documented on a separate page.

• The file system's native API has a more sophisticated error code system, and returns error codes directly from its API functions.

Example usage:

void vAFunction( FF_FILE *pxFile, long lOffset, int iWhence ) { int iReturned; /* Attempt to seek a file using the parameters passed into this function. */ iReturned = ff_fseek( pxFile, lOffset, iWhence ); if( iReturned == 0 ) { /* The call to ff_fseek() passed. */ } else { /* The call to ff_fseek() failed. Obtain the errno to see why. */ iReturned = ff_errno(); if( iReturned == pdFREERTOS_ERRNO_ESPIPE ) { /* The seep position was illegal - outside of the file's space. */ } else if( iReturned == pdFREERTOS_ERRNO_EINVAL ) { /* The value of iWhence was not legal. */ } } } Example use of the ff_errno() API function