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LibrariesinsideFreeRTOS plus FAT

Updated Mar 2025

Reference: errno values

Standard API errno Values

[FreeRTOS-Plus-FAT Standard API Reference]

The FreeRTOS-Plus-FAT file system's standard API uses the same errno values as used by the standard C library. File related functions in standard C library 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.

Similarly, FreeRTOS-Plus-FAT's standard API returns 0 for and -1 for fail, and maintains an errno variable for each RTOS task. A task can retrieve its errno value by calling stdioGET_ERRNO(). The error codes returned by stdioGET_ERRNO() are defined in <projdefs.h> files and are listed below.

ValueConstantDescription
0pdFREERTOS_ERRNO_NONENo such file or directory
2pdFREERTOS_ERRNO_ENOENTNo such file or directory
5pdFREERTOS_ERRNO_EIOI/O error
6pdFREERTOS_ERRNO_ENXIONo such device or address
9pdFREERTOS_ERRNO_EBADFBad file number
11pdFREERTOS_ERRNO_EAGAINNo more processes
11pdFREERTOS_ERRNO_EWOULDBLOCKOperation would block
12pdFREERTOS_ERRNO_ENOMEMNot enough core
13pdFREERTOS_ERRNO_EACCESPermission denied
14pdFREERTOS_ERRNO_EFAULTBad address
16pdFREERTOS_ERRNO_EBUSYMount device busy
17pdFREERTOS_ERRNO_EEXISTFile exists
18pdFREERTOS_ERRNO_EXDEVCross-device link
19pdFREERTOS_ERRNO_ENODEVNo such device
20pdFREERTOS_ERRNO_ENOTDIRNot a directory
21pdFREERTOS_ERRNO_EISDIRIs a directory
22pdFREERTOS_ERRNO_EINVALInvalid argument
28pdFREERTOS_ERRNO_ENOSPCNo space left on device
29pdFREERTOS_ERRNO_ESPIPEIllegal seek
30pdFREERTOS_ERRNO_EROFSRead only file system
42pdFREERTOS_ERRNO_EUNATCHProtocol driver not attached
50pdFREERTOS_ERRNO_EBADEInvalid exchange
79pdFREERTOS_ERRNO_EFTYPEInappropriate file type or format
89pdFREERTOS_ERRNO_ENMFILENo more files
90pdFREERTOS_ERRNO_ENOTEMPTYDirectory not empty
91pdFREERTOS_ERRNO_ENAMETOOLONGFile or path name too long
95pdFREERTOS_ERRNO_EOPNOTSUPPOperation not supported on transport endpoint
105pdFREERTOS_ERRNO_ENOBUFSNo buffer space available
109pdFREERTOS_ERRNO_ENOPROTOOPTProtocol not available
112pdFREERTOS_ERRNO_EADDRINUSEAddress already in use
116pdFREERTOS_ERRNO_ETIMEDOUTConnection timed out
119pdFREERTOS_ERRNO_EINPROGRESSConnection already in progress
120pdFREERTOS_ERRNO_EALREADYSocket already connected
125pdFREERTOS_ERRNO_EADDRNOTAVAILAddress not available
127pdFREERTOS_ERRNO_EISCONNSocket is already connected
128pdFREERTOS_ERRNO_ENOTCONNSocket is not connected
135pdFREERTOS_ERRNO_ENOMEDIUMNo medium inserted
138pdFREERTOS_ERRNO_EILSEQAn invalid UTF-16 sequence was encountered
140pdFREERTOS_ERRNO_ECANCELEDOperation cancelled

Native API errno Values

[FreeRTOS-Plus-FAT Native API Reference]

The file system's native API has a more sophisticated error code system, and returns error codes directly from its API functions. Error codes used by native APIs are defined in <ff_error.h>.