#ifndef VLIBC_ERRNO_H
#define VLIBC_ERRNO_H

/*
 * vlibc — <errno.h>.
 *
 * errno is per-thread state. It lives in a slot of the thread control block
 * (TCB), addressed relative to the x86_64 FS thread pointer; there is no
 * process-global errno object and no compiler-managed TLS (`__thread`) here.
 * The errno macro below expands to a dereference of __errno_location(), the
 * implementation-reserved accessor that returns the address of the calling
 * thread's errno slot. The offset of that slot inside the TCB is the ABI
 * constant VLIBC_TCB_ERRNO_OFF, owned by the internal TCB/ABI headers (see
 * src/internal/errno.h) — this public header is the single canonical home
 * for the errno macro, the __errno_location() declaration, and the E*
 * constant table, so internal code includes it instead of keeping a copy.
 *
 * Levels are cumulative (see include/vlibc/features.h):
 *   Level 1 (onlyposix): POSIX base — strerror.
 *   Level 2 (muslmimic): XSI — strerror_r (the int-returning flavor; the
 *                        GNU char*-returning variant is level 3+ and is
 *                        deliberately not provided).
 *
 * This header includes <vlibc/features.h> itself, so the gates below always
 * see the configured VLIBC_LEVEL even when the caller included no vlibc
 * header first, and <stddef.h> for size_t.
 */

#include <vlibc/features.h>

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Return the address of the calling thread's errno slot.
 *
 * Requires the thread pointer (FS) to be initialized to a TCB whose first
 * word is the TCB's own address — the startup todo owns that bootstrap and
 * sets it before any code that can touch errno runs. This function itself
 * performs no setup and no other TCB access.
 *
 * The name sits in the implementation-reserved namespace deliberately: it is
 * this libc's private errno accessor, not public API.
 */
int *
__errno_location(void); // NOLINT(bugprone-reserved-identifier)

/* The conventional errno lvalue; resolves to the caller's TCB slot. */
#define errno (*__errno_location())

/*
 * Error numbers: the Linux errno ABI (asm-generic/errno-base.h plus
 * asm-generic/errno.h, which is the table x86_64 uses), transcribed as
 * kernel-ABI facts. These values are fixed and shared with the kernel.
 * Values 41 and 58 do not exist in the ABI (EWOULDBLOCK and EDEADLOCK are
 * aliases of EAGAIN and EDEADLK); EHWPOISON is the last defined value.
 */

#define EPERM 1             /* Operation not permitted */
#define ENOENT 2            /* No such file or directory */
#define ESRCH 3             /* No such process */
#define EINTR 4             /* Interrupted system call */
#define EIO 5               /* I/O error */
#define ENXIO 6             /* No such device or address */
#define E2BIG 7             /* Argument list too long */
#define ENOEXEC 8           /* Exec format error */
#define EBADF 9             /* Bad file descriptor */
#define ECHILD 10           /* No child processes */
#define EAGAIN 11           /* Try again */
#define ENOMEM 12           /* Out of memory */
#define EACCES 13           /* Permission denied */
#define EFAULT 14           /* Bad address */
#define ENOTBLK 15          /* Block device required */
#define EBUSY 16            /* Device or resource busy */
#define EEXIST 17           /* File exists */
#define EXDEV 18            /* Cross-device link */
#define ENODEV 19           /* No such device */
#define ENOTDIR 20          /* Not a directory */
#define EISDIR 21           /* Is a directory */
#define EINVAL 22           /* Invalid argument */
#define ENFILE 23           /* File table overflow */
#define EMFILE 24           /* Too many open files */
#define ENOTTY 25           /* Not a typewriter */
#define ETXTBSY 26          /* Text file busy */
#define EFBIG 27            /* File too large */
#define ENOSPC 28           /* No space left on device */
#define ESPIPE 29           /* Illegal seek */
#define EROFS 30            /* Read-only file system */
#define EMLINK 31           /* Too many links */
#define EPIPE 32            /* Broken pipe */
#define EDOM 33             /* Math argument out of domain of func */
#define ERANGE 34           /* Math result not representable */
#define EDEADLK 35          /* Resource deadlock would occur */
#define ENAMETOOLONG 36     /* File name too long */
#define ENOLCK 37           /* No record locks available */
#define ENOSYS 38           /* Invalid system call number */
#define ENOTEMPTY 39        /* Directory not empty */
#define ELOOP 40            /* Too many symbolic links encountered */
#define EWOULDBLOCK EAGAIN  /* Operation would block */
#define ENOMSG 42           /* No message of desired type */
#define EIDRM 43            /* Identifier removed */
#define ECHRNG 44           /* Channel number out of range */
#define EL2NSYNC 45         /* Level 2 not synchronized */
#define EL3HLT 46           /* Level 3 halted */
#define EL3RST 47           /* Level 3 reset */
#define ELNRNG 48           /* Link number out of range */
#define EUNATCH 49          /* Protocol driver not attached */
#define ENOCSI 50           /* No CSI structure available */
#define EL2HLT 51           /* Level 2 halted */
#define EBADE 52            /* Invalid exchange */
#define EBADR 53            /* Invalid request descriptor */
#define EXFULL 54           /* Exchange full */
#define ENOANO 55           /* No anode */
#define EBADRQC 56          /* Invalid request code */
#define EBADSLT 57          /* Invalid slot */
#define EDEADLOCK EDEADLK   /* File locking deadlock error */
#define EBFONT 59           /* Bad font file format */
#define ENOSTR 60           /* Device not a stream */
#define ENODATA 61          /* No data available */
#define ETIME 62            /* Timer expired */
#define ENOSR 63            /* Out of streams resources */
#define ENONET 64           /* Machine is not on the network */
#define ENOPKG 65           /* Package not installed */
#define EREMOTE 66          /* Object is remote */
#define ENOLINK 67          /* Link has been severed */
#define EADV 68             /* Advertise error */
#define ESRMNT 69           /* Srmount error */
#define ECOMM 70            /* Communication error on send */
#define EPROTO 71           /* Protocol error */
#define EMULTIHOP 72        /* Multihop attempted */
#define EDOTDOT 73          /* RFS specific error */
#define EBADMSG 74          /* Not a data message */
#define EOVERFLOW 75        /* Value too large for defined data type */
#define ENOTUNIQ 76         /* Name not unique on network */
#define EBADFD 77           /* File descriptor in bad state */
#define EREMCHG 78          /* Remote address changed */
#define ELIBACC 79          /* Can not access a needed shared library */
#define ELIBBAD 80          /* Accessing a corrupted shared library */
#define ELIBSCN 81          /* .lib section in a.out corrupted */
#define ELIBMAX 82          /* Attempting to link in too many shared libraries */
#define ELIBEXEC 83         /* Cannot exec a shared library directly */
#define EILSEQ 84           /* Illegal byte sequence */
#define ERESTART 85         /* Interrupted system call should be restarted */
#define ESTRPIPE 86         /* Streams pipe error */
#define EUSERS 87           /* Too many users */
#define ENOTSOCK 88         /* Socket operation on non-socket */
#define EDESTADDRREQ 89     /* Destination address required */
#define EMSGSIZE 90         /* Message too long */
#define EPROTOTYPE 91       /* Protocol wrong type for socket */
#define ENOPROTOOPT 92      /* Protocol not available */
#define EPROTONOSUPPORT 93  /* Protocol not supported */
#define ESOCKTNOSUPPORT 94  /* Socket type not supported */
#define EOPNOTSUPP 95       /* Operation not supported on transport endpoint */
#define EPFNOSUPPORT 96     /* Protocol family not supported */
#define EAFNOSUPPORT 97     /* Address family not supported by protocol */
#define EADDRINUSE 98       /* Address already in use */
#define EADDRNOTAVAIL 99    /* Cannot assign requested address */
#define ENETDOWN 100        /* Network is down */
#define ENETUNREACH 101     /* Network is unreachable */
#define ENETRESET 102       /* Network dropped connection because of reset */
#define ECONNABORTED 103    /* Software caused connection abort */
#define ECONNRESET 104      /* Connection reset by peer */
#define ENOBUFS 105         /* No buffer space available */
#define EISCONN 106         /* Transport endpoint is already connected */
#define ENOTCONN 107        /* Transport endpoint is not connected */
#define ESHUTDOWN 108       /* Cannot send after transport endpoint shutdown */
#define ETOOMANYREFS 109    /* Too many references: cannot splice */
#define ETIMEDOUT 110       /* Connection timed out */
#define ECONNREFUSED 111    /* Connection refused */
#define EHOSTDOWN 112       /* Host is down */
#define EHOSTUNREACH 113    /* No route to host */
#define EALREADY 114        /* Operation already in progress */
#define EINPROGRESS 115     /* Operation now in progress */
#define ESTALE 116          /* Stale file handle */
#define EUCLEAN 117         /* Structure needs cleaning */
#define ENOTNAM 118         /* Not a XENIX named type file */
#define ENAVAIL 119         /* No XENIX semaphores available */
#define EISNAM 120          /* Is a named type file */
#define EREMOTEIO 121       /* Remote I/O error */
#define EDQUOT 122          /* Quota exceeded */
#define ENOMEDIUM 123       /* No medium found */
#define EMEDIUMTYPE 124     /* Wrong medium type */
#define ECANCELED 125       /* Operation canceled */
#define ENOKEY 126          /* Required key not available */
#define EKEYEXPIRED 127     /* Key has expired */
#define EKEYREVOKED 128     /* Key has been revoked */
#define EKEYREJECTED 129    /* Key was rejected by service */
#define EOWNERDEAD 130      /* Owner died */
#define ENOTRECOVERABLE 131 /* State not recoverable */
#define ERFKILL 132         /* Operation not possible due to RF-kill */
#define EHWPOISON 133       /* Memory page has hardware error */

/*
 * Return a pointer to the message string for errnum. The string for a known
 * value points to immutable static storage and is safe to keep across calls;
 * an unknown value yields "Unknown error <errnum>", formatted into shared
 * static storage whose contents a later call may overwrite (unknown errno
 * values are a rare diagnostic path; see strerror.c). Never returns NULL.
 *
 * No intent attribute: the unknown-value path writes shared storage.
 */
char *
strerror(int errnum);

#if VLIBC_LEVEL_GE(2)
/* Level 2 (muslmimic): XSI. */

/*
 * XSI strerror_r: copy the message for errnum into buf, truncated to buflen
 * and always NUL-terminated when buflen > 0, and return 0 — including for
 * unknown errnum values, whose text is "Unknown error <errnum>". When buflen
 * is 0 nothing is written and 0 is returned; when buf is NULL and buflen > 0,
 * EINVAL is returned. The GNU char*-returning variant is deliberately not
 * provided.
 *
 * No intent attribute: it writes memory.
 */
int
strerror_r(int errnum, char *buf, size_t buflen);
#endif /* VLIBC_LEVEL_GE(2) */

#ifdef __cplusplus
}
#endif

#endif /* VLIBC_ERRNO_H */