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The format string syntax and semantics is the same for all of the functions in the printf-like family. Mismatch between the format specifiers and count and type of values can cause a crash or vulnerability. The printf format string is complementary to the scanf format string, which provides formatted input (lexing a.k.a. parsing). Both format ...
The formatting placeholders in scanf are more or less the same as that in printf, its reverse function.As in printf, the POSIX extension n$ is defined. [2]There are rarely constants (i.e., characters that are not formatting placeholders) in a format string, mainly because a program is usually not designed to read known data, although scanf does accept these if explicitly specified.
For function that manipulate strings, modern object-oriented languages, like C# and Java have immutable strings and return a copy (in newly allocated dynamic memory), while others, like C manipulate the original string unless the programmer copies data to a new string.
In Visual Basic (and Visual Basic for Applications) the Variant data type is a tagged union that can be used to represent any other data type (for example, integer, floating-point, single- and double-precision, object, etc.) except fixed-length string type. In Visual Basic, any variable not declared explicitly or the type of which is not ...
It defines macros for printf format string and scanf format string specifiers corresponding to the types defined in <stdint.h> and several functions for working with the intmax_t and uintmax_t types. This header was added in C99.
Both take one argument that specifies the formatting of the output, and any number of arguments that provide the values to be formatted. Variadic functions can expose type-safety problems in some languages. For instance, C's printf, if used incautiously, can give rise to a class of security holes known as format string attacks.
Rust does not have general string interpolation, but provides similar functionality via macros, referred to as "Captured identifiers in format strings", introduced in version 1.58.0, released 2022-01-13. [15] Rust provides formatting via the std::fmt module, which is interfaced with through various macros such as format!, write!, and print!.
Some C implementations provide C extensions that allow the compiler to check for the proper use of format strings and sentinels. Barring these extensions, the compiler usually cannot check whether the unnamed arguments passed are of the type the function expects, or convert them to the required type.