| Previous | Next |
| EBADSLT | EISCONN |
EBADRQC
This page examines invalid legacy request code. The driver recognized the request channel but not the request-code value for that interface version.
Historical and API context
Linux UAPI compatibility: For invalid legacy request code, this symbol remains in Linux headers for compatibility but is outside the small portable POSIX errno set. The wording of invalid legacy request code often points to System V, STREAMS, XENIX, or an old device-control ABI rather than a modern generic filesystem or socket failure. Within Linux UAPI compatibility, the wording attached to EBADRQC is a clue to the original interface, not proof that a similarly named modern subsystem returned it.
These Linux symbols are largely inherited from System V and old communications or XENIX interfaces for the invalid legacy request code case. The symbolic name is ABI evidence, but its wording alone does not identify a modern subsystem while evaluating invalid legacy request code.
Interpretation limit. Confirm the returning call and implementation before assigning historical layer names to a current proprietary driver when diagnosing invalid legacy request code.
Reconstruct the returning call
| Evidence | Question it answers |
|---|---|
| Request code, ioctl family, structure version, driver/module version, and feature negotiation. | Ties invalid legacy request code to one live API object instead of a translated message. |
| Numeric errno and symbolic name from the exact target architecture/header in an investigation of invalid legacy request code. | Shows whether invalid legacy request code arose in the caller ABI, wrapper, or provider. |
| Strace or equivalent showing the syscall/ioctl that first set errno for the invalid legacy request code case. | Preserves the first boundary before errno can be overwritten for invalid legacy request code. |
| Whether the binary is native, containerized, emulated, or linked to a legacy compatibility library while evaluating invalid legacy request code. | Provides a same-platform known-good comparison for invalid legacy request code. |
Capture errno immediately after the failing call that produced invalid legacy request code, before formatting, tracing, allocation, or cleanup code runs. For invalid legacy request code, retain the function return value as well because many C interfaces signal failure there and use errno only as secondary detail.
A small reproduction
- Issue a documented baseline request code on the same handle. Keep the binary, header ABI, and provider fixed while testing invalid legacy request code.
- Compare with a modern supported API that performs the nearest equivalent operation in an investigation of invalid legacy request code. Record whether the control reaches the same syscall or runtime boundary as invalid legacy request code.
- Record errno immediately after the failing call before any logging call can overwrite it for the invalid legacy request code case. A changed errno after this test is a new boundary, not another spelling of invalid legacy request code.
Two observations are especially discriminating here: Request code, ioctl family, structure version, driver/module version, and feature negotiation. Use this control for comparison: issue a documented baseline request code on the same handle. For invalid legacy request code, those two observations separate a stale identifier or unsupported request from a provider-wide failure without broad changes to the host.
Portability traps
| Tempting assumption | Safer interpretation |
|---|---|
| The English phrase is assumed to be portable | invalid legacy request code belongs to Linux UAPI compatibility; verify the target headers and returning API before applying another platform's errno table |
| A retry succeeded and erased the original evidence | The retry can replace invalid legacy request code with a different state; preserve the first call, numeric value, and object generation beforehand |
If a wrapper converts invalid legacy request code to an exception or Boolean, instrument below that wrapper. For invalid legacy request code, the decisive record is the syscall, ioctl, CRT function, or compatibility entry point that first exposed the value.
Correction and acceptance
Targeted correction. Use a code supported by the loaded driver and compile against matching headers.
Regression proof. Supported codes work and unknown codes fail before consuming payload data. Verify one supported boundary case and one deliberate negative case so handling of invalid legacy request code remains explicit.
Technical references
These owner-maintained or standards-based sources define the namespace and subsystem contract needed to verify Linux UAPI compatibility EBADRQC on the deployed platform version.
- Linux man-pages: errno(3) — defines the status namespace used for invalid legacy request code.
- Linux kernel: asm-generic errno definitions — documents the API or lifecycle boundary behind invalid legacy request code.
- GNU C Library: error codes — provides ABI, implementation, or protocol context for invalid legacy request code.
- illumos: STREAMS programming documentation — supports the portability and verification limits for invalid legacy request code.
Looking for a different code? Search another status or error code.