An implementation of a print statement in C++.
#include "print.h"
print expression[, expression]*
print "format" % expression[, expression]*
eprint expression[, expression]*
eprint "format" % expression[, expression]*
/** examples **/
print "Hello", "world", time(0); // Hello world 1360826578
print "name=%q age=%s" % "Alex", 26; // name="Alex" age=26
int numbers[] = { 1, 2, 3 };
print numbers; // [1, 2, 3]
std::vector<std::string> things = {"apples", "oranges", "elephants"};
print things; // [apples, oranges, elephants]
The first form converts each expression into a string and prints it to standard output, with each expression separated by a space and a terminating newline at the end. eprint is similar except it prints to standard error.
The second form uses a format string similar to printf().
%sThe argument is printed directly.%qThe argument is quoted.
Expressions are converted to strings according to their type, as follows:
char*are output as NUL-terminated strings like %s.int,short,long,signed char,unsigned charare printed in decimal notation like with %d.charprints the charcter like %c.void *or any other kind of pointers prints ths pointer in hex like %p.double,floatprints the number in decimal notation like %g.boolprints 'true' or 'false'- A type that defines a member function called
c_str()is converted to a string by calling this function. - A type than can be streamed to an
std::ostreamlikestd::cout << thingbut does not have ac_str()member function is converted to a string using<<. - A type that has a
begin()member function that returns in iterator but does not have ac_str()member function is printed like a list, e.g.["one", "two"]. std:map,std::unordered_map,std::multimap,std::unordered_multipmap,QHash,QMap,QMultiHash,QMultiMapare special-cased and printed like dictionaries, e.g.{"foo": "bar"}.QStringis printed as a string.std::pairis rendered as("first", "second").
The easiest way to use this is to clone this repo and copy the file print.h into your project.
Then simply
#include "print.h"` at the top of the file, but after the system #includess.
print is thread and exception safe.
The output stream is locked once before anything is printed and then unlocked at the end inside a destructor. This ensures that the whole line will be printed without being interleaved with output from another thread.
Internally, the fwrite() family of function from C standard library are used for output. C++ streams are not used at all.
In benchmakrs print is a little bit faster than cout and a little bit slower than printf.
print.h includes stdio.h and nothing else.
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