1VSNPRINTF(9)               Basic C Library Functions              VSNPRINTF(9)
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NAME

6       vsnprintf - Format a string and place it in a buffer
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SYNOPSIS

9       int vsnprintf(char * buf, size_t size, const char * fmt, va_list args);
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ARGUMENTS

12       buf
13           The buffer to place the result into
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15       size
16           The size of the buffer, including the trailing null space
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18       fmt
19           The format string to use
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21       args
22           Arguments for the format string
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DESCRIPTION

25       This function follows C99 vsnprintf, but has some extensions: pS output
26       the name of a text symbol with offset ps output the name of a text
27       symbol without offset pF output the name of a function pointer with its
28       offset pf output the name of a function pointer without its offset pB
29       output the name of a backtrace symbol with its offset pR output the
30       address range in a struct resource with decoded flags pr output the
31       address range in a struct resource with raw flags pb output the bitmap
32       with field width as the number of bits pbl output the bitmap as range
33       list with field width as the number of bits pM output a 6-byte MAC
34       address with colons pMR output a 6-byte MAC address with colons in
35       reversed order pMF output a 6-byte MAC address with dashes pm output a
36       6-byte MAC address without colons pmR output a 6-byte MAC address
37       without colons in reversed order pI4 print an IPv4 address without
38       leading zeros pi4 print an IPv4 address with leading zeros pI6 print an
39       IPv6 address with colons pi6 print an IPv6 address without colons pI6c
40       print an IPv6 address as specified by RFC 5952 pIS depending on
41       sa_family of 'struct sockaddr *' print IPv4/IPv6 address piS depending
42       on sa_family of 'struct sockaddr *' print IPv4/IPv6 address pU[bBlL]
43       print a UUID/GUID in big or little endian using lower or upper case.
44       %*ph[CDN] a variable-length hex string with a separator (supports up to
45       64 bytes of the input) pc print a cpumask as comma-separated list n is
46       ignored
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48       ** Please update Documentation/printk-formats.txt when making changes
49       **
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51       The return value is the number of characters which would be generated
52       for the given input, excluding the trailing '\0', as per ISO C99. If
53       you want to have the exact number of characters written into buf as
54       return value (not including the trailing '\0'), use vscnprintf. If the
55       return is greater than or equal to size, the resulting string is
56       truncated.
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58       If you're not already dealing with a va_list consider using snprintf.
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61Kernel Hackers Manual 3.10         June 2019                      VSNPRINTF(9)
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