EFBIG

EFBIG is an errno value used on Unix-like systems to indicate that a file operation failed because the file would become too large. It is defined in the C standard library headers (such as errno.h) and is returned by kernel calls when a request would extend a file beyond the system, filesystem, or per-process limits.

Causes and scope: EFBIG occurs when an operation would enlarge a file beyond the maximum size supported by the filesystem or by the process’s limits. Common operations that can trigger this error include writing to a file in a way that would lengthen it, or using ftruncate to set a file size that exceeds permitted limits. The specific limit depends on the filesystem, architecture, and process resource limits (for example, RLIMIT_FSIZE can restrict maximum file size that a process may create or modify).

Platform notes: While the general meaning is consistent across Unix-like systems, the numeric value of EFBIG and the exact conditions that produce it can vary between platforms. It is distinct from related errors such as ENOSPC (no space left on device) and EINVAL (invalid argument).

Examples: A program attempting to append data to a file on a 32-bit system where the maximum file size is limited may receive EFBIG when the write would exceed that limit. Similarly, trying to resize a file beyond RLIMIT_FSIZE or filesystem-imposed limits can yield EFBIG.

See also: ENOSPC, EINVAL, RLIMIT_FSIZE.