---
name: "X509_ACERT_add1_attr"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/X509_ACERT_add1_attr"
---

# X509\_ACERT\_add1\_attr(3ssl)

X509\_ACERT attribute functions

## NAME

X509\_ACERT\_add1\_attr, X509\_ACERT\_add1\_attr\_by\_NID, X509\_ACERT\_add1\_attr\_by\_OBJ, X509\_ACERT\_add1\_attr\_by\_txt, X509\_ACERT\_delete\_attr - X509\_ACERT attribute functions

## SYNOPSIS

```
 #include <openssl/x509_acert.h>
 int X509_ACERT_add1_attr(X509_ACERT *x, X509_ATTRIBUTE *attr);
 int X509_ACERT_add1_attr_by_NID(X509_ACERT *x, int nid, int type,
                                 const void *bytes, int len);
 int X509_ACERT_add1_attr_by_OBJ(X509_ACERT *x, const ASN1_OBJECT *obj,
                                 int type, const void *bytes, int len);
 int X509_ACERT_add1_attr_by_txt(X509_ACERT *x, const char *attrname, int type,
                                 const unsigned char *bytes, int len);
 X509_ATTRIBUTE *X509_ACERT_delete_attr(X509_ACERT *x, int loc);
```

## DESCRIPTION

**X509\_ACERT\_add1\_attr()** adds a constructed X509\_ATTRIBUTE **attr** to the existing X509\_ACERT structure **x**.

**X509\_ACERT\_add1\_attr\_by\_NID()** and **X509\_ACERT\_add1\_attr\_by\_OBJ()** add an attribute of type *nid* or *obj* with a value of ASN1 type *type* constructed using *len* bytes from *bytes*.

**X509\_ACERT\_add1\_attr\_by\_txt()** adds an attribute of type *attrname* with a value of ASN1 type *type* constructed using *len* bytes from *bytes*.

**X509\_ACERT\_delete\_attr()** will delete the *loc*th attribute from *x* and return a pointer to it or NULL if there are fewer than *loc* attributes contained in *x*.

## RETURN VALUES

**X509\_ACERT\_add1\_attr()**, **X509\_ACERT\_add1\_attr\_by\_NID()**, and **X509\_ACERT\_add1\_attr\_by\_OBJ()** return 1 for success and 0 for failure.

**X509\_ACERT\_delete\_attr()** returns a **X509\_ATTRIBUTE** pointer on success or NULL on failure.

## SEE ALSO

**X509\_ACERT\_get\_attr\_count**(3)

## HISTORY

**X509\_ACERT\_add1\_attr()**, **X509\_ACERT\_add1\_attr\_by\_NID()**, **X509\_ACERT\_add1\_attr\_by\_OBJ()**, **X509\_ACERT\_add1\_attr\_by\_txt()** and **X509\_ACERT\_delete\_attr()** were added in OpenSSL 3.4.

## COPYRIGHT

Copyright 2023-2024 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance with the License.  You can obtain a copy in the file LICENSE in the source distribution or at \<https://www.openssl.org/source/license.html\>.