Reference: errno Values

[FreeRTOS+FAT Standard API Reference]

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. A task can retrieve its errno value by calling ff_errno(). The values returned by ff_errno() are defined below.

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.

Value	Constant	Description
0	pdFREERTOS_ERRNO_NONE	No such file or directory
2	pdFREERTOS_ERRNO_ENOENT	No such file or directory
5	pdFREERTOS_ERRNO_EIO	I/O error
6	pdFREERTOS_ERRNO_ENXIO	No such device or address
9	pdFREERTOS_ERRNO_EBADF	Bad file number
11	pdFREERTOS_ERRNO_EAGAIN	No more processes
11	pdFREERTOS_ERRNO_EWOULDBLOCK	Operation would block
12	pdFREERTOS_ERRNO_ENOMEM	Not enough core
13	pdFREERTOS_ERRNO_EACCES	Permission denied
14	pdFREERTOS_ERRNO_EFAULT	Bad address
16	pdFREERTOS_ERRNO_EBUSY	Mount device busy
17	pdFREERTOS_ERRNO_EEXIST	File exists
18	pdFREERTOS_ERRNO_EXDEV	Cross-device link
19	pdFREERTOS_ERRNO_ENODEV	No such device
20	pdFREERTOS_ERRNO_ENOTDIR	Not a directory
21	pdFREERTOS_ERRNO_EISDIR	Is a directory
22	pdFREERTOS_ERRNO_EINVAL	Invalid argument
28	pdFREERTOS_ERRNO_ENOSPC	No space left on device
29	pdFREERTOS_ERRNO_ESPIPE	Illegal seek
30	pdFREERTOS_ERRNO_EROFS	Read only file system
42	pdFREERTOS_ERRNO_EUNATCH	Protocol driver not attached
50	pdFREERTOS_ERRNO_EBADE	Invalid exchange
79	pdFREERTOS_ERRNO_EFTYPE	Inappropriate file type or format
89	pdFREERTOS_ERRNO_ENMFILE	No more files
90	pdFREERTOS_ERRNO_ENOTEMPTY	Directory not empty
91	pdFREERTOS_ERRNO_ENAMETOOLONG	File or path name too long
95	pdFREERTOS_ERRNO_EOPNOTSUPP	Operation not supported on transport endpoint
105	pdFREERTOS_ERRNO_ENOBUFS	No buffer space available
109	pdFREERTOS_ERRNO_ENOPROTOOPT	Protocol not available
112	pdFREERTOS_ERRNO_EADDRINUSE	Address already in use
116	pdFREERTOS_ERRNO_ETIMEDOUT	Connection timed out
119	pdFREERTOS_ERRNO_EINPROGRESS	Connection already in progress
120	pdFREERTOS_ERRNO_EALREADY	Socket already connected
125	pdFREERTOS_ERRNO_EADDRNOTAVAIL	Address not available
127	pdFREERTOS_ERRNO_EISCONN	Socket is already connected
128	pdFREERTOS_ERRNO_ENOTCONN	Socket is not connected
135	pdFREERTOS_ERRNO_ENOMEDIUM	No medium inserted
138	pdFREERTOS_ERRNO_EILSEQ	An invalid UTF-16 sequence was encountered
140	pdFREERTOS_ERRNO_ECANCELED	Operation cancelled