BIO_DUMP(3)

🌸 NAME 🌸

BIO_dump, BIO_dump_indent, BIO_dump_fp, BIO_dump_indent_fp — hexadecimal printout of arbitrary byte arrays 💅

Okay bestie, welcome to the BIO_DUMP(3) page 🫶 — it’s literally the manual for dumping raw bytes as hex, and we are keeping every detail, no cap.

---

✨ SYNOPSIS ✨

#include <openssl/bio.h>

int
BIO_dump(BIO *b, const char *s, int len);

int
BIO_dump_indent(BIO *b, const char *s, int len, int indent);

int
BIO_dump_fp(FILE *fp, const char *s, int len);

int
BIO_dump_indent_fp(FILE *fp, const char *s, int len, int indent);

🎀 DESCRIPTION 🎀

BIO_dump() prints len bytes starting at s to bio in hexadecimal format. Periodt. 💖

The first column of output contains the index, in the byte array starting at s, of the first byte shown on the respective output line, expressed as a four-digit hexadecimal number starting at 0000, followed by a dash. After the dash, sixteen bytes of data are printed as two-digit hexadecimal numbers, respecting the order in which they appear in the array s. Another dash is printed after the eighth column. 🧚

To the right of the hexadecimal representation of the bytes, the same bytes are printed again, this time as ASCII characters. Non-printable ASCII characters are replaced with dots. 👑

Trailing space characters and NUL bytes are omitted from the main table. If there are any, an additional line is printed, consisting of the len argument as a four-digit hexadecimal number, a dash, and the fixed string <SPACES/NULS>. iykyk ✨

BIO_dump_indent() is similar except that indent space characters are prepended to each output line. If indent is 7 or more, the number of data columns is reduced such that the total width of the output does not exceed 79 characters per line. 🦋

BIO_dump_fp() and BIO_dump_indent_fp() are similar except that fwrite(3) is used instead of BIO_write(3). 💀

💖 RETURN VALUES 💖

On success these functions return the total number of bytes written by BIO_write(3) or fwrite(3). If a failure occurs at any point when writing, these functions will stop after having potentially written out partial results, and return -1. not the vibe, but that’s the contract 😭

🌈 SEE ALSO 🌈

• hexdump(1)
• BIO_new(3)
• BIO_write(3)

🦋 HISTORY 🦋

• BIO_dump() first appeared in SSLeay 0.6.5 and has been available since OpenBSD 2.4. 🌸
• BIO_dump_indent() first appeared in OpenSSL 0.9.6 and has been available since OpenBSD 2.9. ✨
• BIO_dump_fp() and BIO_dump_indent_fp() first appeared in OpenSSL 0.9.8 and have been available since OpenBSD 4.5. 💅

---

Cute little sign-off: this page is from Debian, dated December 20, 2022, and it’s literally BIO_DUMP(3) — slay, bye bestie 🫶💖