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openssl-1.0.2f/doc/crypto/ASN1_STRING_print_ex.pod

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+=pod
+
+=head1 NAME
+
+ASN1_STRING_print_ex, ASN1_STRING_print_ex_fp, ASN1_STRING_print - ASN1_STRING output routines.
+
+=head1 SYNOPSIS
+
+ #include <openssl/asn1.h>
+
+ int ASN1_STRING_print_ex(BIO *out, ASN1_STRING *str, unsigned long flags);
+ int ASN1_STRING_print_ex_fp(FILE *fp, ASN1_STRING *str, unsigned long flags);
+ int ASN1_STRING_print(BIO *out, ASN1_STRING *str);
+
+
+=head1 DESCRIPTION
+
+These functions output an B<ASN1_STRING> structure. B<ASN1_STRING> is used to
+represent all the ASN1 string types.
+
+ASN1_STRING_print_ex() outputs B<str> to B<out>, the format is determined by
+the options B<flags>. ASN1_STRING_print_ex_fp() is identical except it outputs
+to B<fp> instead.
+
+ASN1_STRING_print() prints B<str> to B<out> but using a different format to
+ASN1_STRING_print_ex(). It replaces unprintable characters (other than CR, LF)
+with '.'.
+
+=head1 NOTES
+
+ASN1_STRING_print() is a legacy function which should be avoided in new applications.
+
+Although there are a large number of options frequently B<ASN1_STRFLGS_RFC2253> is 
+suitable, or on UTF8 terminals B<ASN1_STRFLGS_RFC2253 & ~ASN1_STRFLGS_ESC_MSB>.
+
+The complete set of supported options for B<flags> is listed below.
+
+Various characters can be escaped. If B<ASN1_STRFLGS_ESC_2253> is set the characters
+determined by RFC2253 are escaped. If B<ASN1_STRFLGS_ESC_CTRL> is set control
+characters are escaped. If B<ASN1_STRFLGS_ESC_MSB> is set characters with the
+MSB set are escaped: this option should B<not> be used if the terminal correctly
+interprets UTF8 sequences.
+
+Escaping takes several forms.
+
+If the character being escaped is a 16 bit character then the form "\UXXXX" is used
+using exactly four characters for the hex representation. If it is 32 bits then
+"\WXXXXXXXX" is used using eight characters of its hex representation. These forms
+will only be used if UTF8 conversion is not set (see below).
+
+Printable characters are normally escaped using the backslash '\' character. If
+B<ASN1_STRFLGS_ESC_QUOTE> is set then the whole string is instead surrounded by
+double quote characters: this is arguably more readable than the backslash
+notation. Other characters use the "\XX" using exactly two characters of the hex
+representation.
+
+If B<ASN1_STRFLGS_UTF8_CONVERT> is set then characters are converted to UTF8
+format first. If the terminal supports the display of UTF8 sequences then this
+option will correctly display multi byte characters.
+
+If B<ASN1_STRFLGS_IGNORE_TYPE> is set then the string type is not interpreted at
+all: everything is assumed to be one byte per character. This is primarily for
+debugging purposes and can result in confusing output in multi character strings.
+
+If B<ASN1_STRFLGS_SHOW_TYPE> is set then the string type itself is printed out
+before its value (for example "BMPSTRING"), this actually uses ASN1_tag2str().
+
+The content of a string instead of being interpreted can be "dumped": this just
+outputs the value of the string using the form #XXXX using hex format for each
+octet.
+
+If B<ASN1_STRFLGS_DUMP_ALL> is set then any type is dumped.
+
+Normally non character string types (such as OCTET STRING) are assumed to be
+one byte per character, if B<ASN1_STRFLGS_DUMP_UNKNOWN> is set then they will
+be dumped instead.
+
+When a type is dumped normally just the content octets are printed, if 
+B<ASN1_STRFLGS_DUMP_DER> is set then the complete encoding is dumped
+instead (including tag and length octets).
+
+B<ASN1_STRFLGS_RFC2253> includes all the flags required by RFC2253. It is
+equivalent to:
+ ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB |
+ ASN1_STRFLGS_UTF8_CONVERT | ASN1_STRFLGS_DUMP_UNKNOWN ASN1_STRFLGS_DUMP_DER
+
+=head1 SEE ALSO
+
+L<X509_NAME_print_ex(3)|X509_NAME_print_ex(3)>,
+L<ASN1_tag2str(3)|ASN1_tag2str(3)>
+
+=head1 HISTORY
+
+TBA
+
+=cut