X509V3_EXTENSIONS_PRINT(3)

X509V3_EXTENSIONS_PRINT(3) 💅 pretty-print an array of X.509 extensions

okay so hi bestie 🫶 this one is from the Library Functions Manual, and it’s all about X509V3_extensions_print() in libcrypto. It’s a little printing goblin for X.509 extensions, and yes it’s niche, but we’re gonna slay it ✨

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🌸 NAME

X509V3_extensions_print — pretty-print an array of X.509 extensions

🎀 SYNOPSIS

library “libcrypto” #include <openssl/x509v3.h>

int
X509V3_extensions_print(BIO *bio, char *title,
    const STACK_OF(X509_EXTENSION) *sk, unsigned long flags,
    int indent);

💅 DESCRIPTION

So for every single member of the variable sized array sk, X509V3_extensions_print() prints the following info to bio, in this exact order:

• The extension type, as printed by i2a_ASN1_OBJECT(3).
• If the extension is critical, the fixed string "critical" — yes, literally that string 👑
• A human-readable representation of the data inside the extension, as printed by X509V3_EXT_print(3), with flags passed through. If that function indicates failure, the BER-encoded data of the extension is dumped with ASN1_STRING_print(3) without decoding it first. In both cases, an indent incremented by 4 space characters is used.

If sk is a NULL pointer or empty, X509V3_extensions_print() prints nothing and indicates success 💖

Unless title is NULL, it is printed on its own output line before the rest of the output, and indent is increased by 4 space characters. This additional global indentation is cumulative to the one applied to individual extensions mentioned above 🫶

🔥 RETURN VALUES

X509V3_extensions_print() is intended to return 1 on success or 0 if an error occurs.

“intended” is doing a lot of heavy lifting here, bestie — peep the BUGS section before you trust it with your whole life 💀

🦋 SEE ALSO

• BIO_new(3)
• STACK_OF(3)
• X509_EXTENSION_get_critical(3)
• X509_get0_extensions(3)
• X509_get_ext(3)
• X509V3_EXT_print(3)

🌈 HISTORY

X509V3_extensions_print() first appeared in OpenSSL 0.9.7 and has been available since OpenBSD 3.2 ✨

💀 BUGS

Many parsing and printing errors are silently ignored, and the function may return indicating success even though sk contains invalid data. Even if all the data is valid, success may be indicated even when the information printed is incomplete for various reasons, for example due to memory allocation failures or I/O errors 😭

no cap: this is giving “trust me bro” energy. It can say success while stuff is invalid or incomplete, so don’t treat the return value like a flawless vibe check 🙈

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source/version: Debian · date: June 8, 2025 — mwah, and that’s the Library Functions Manual sign-off bestie 💋🎀