ObjectiveC的NSLog和Printf语句之间的区别

I want to know about the difference between the NSLog and the Printf statement in Objective-C (for application purpose...!)

我想知道Objective-C中NSLog和Printf语句之间的区别（用于应用程序......！）

Why do all developer use NSLog instead of Printf ?

为什么所有开发人员都使用NSLog而不是Printf？

Both look similar, but what is the difference in internal working?

两者看起来相似，但内部工作有什么不同？

At which point can they be differentiated ?

他们可以在哪个方面加以区分？

4 个解决方案

#1

printf() is a C standard library function, accepting a C string constant (const char *) as its format argument. printf() writes to stdout.

printf（）是一个C标准库函数，接受一个C字符串常量（const char *）作为其格式参数。 printf（）写入stdout。
NSLog() is a Foundation function, accepting a constant NSString as format, and has an extended format specifier set (for example, printf() does't print objects specified by %@, NSLog() does). NSLog() also prints the process name and date before it prints the actual format and writes to sdterr.

NSLog（）是一个Foundation函数，接受一个常量NSString作为格式，并具有一个扩展格式说明符集（例如，printf（）不打印由％@，NSLog（）指定的对象）。 NSLog（）还会在打印实际格式之前打印进程名称和日期，并写入sdterr。

Basically, we can say that NSLog() is an extended printf() Style function for Objective-C (more precisely, Cocoa and Cocoa Touch) and specific purposes.

基本上，我们可以说NSLog（）是Objective-C（更确切地说，Cocoa和Cocoa Touch）和特定用途的扩展printf（）Style函数。

#2

NSLog is like a printf, but it does a bit more:

NSLog就像一个printf，但它做得更多：

A timestamp is added to the output.
时间戳添加到输出中。
The output is sent to the Xcode console, or whatever stderr is defined as.
输出发送到Xcode控制台，或者定义为stderr的任何内容。
It accepts all the printf specifiers, but it also accepts the @ operator for objects which displays the string provided by the object's description method. (description is part of NSObject, so all objects can override it to return a string that describes the object).
它接受所有printf说明符，但它也接受@运算符用于显示对象描述方法提供的字符串的对象。（描述是NSObject的一部分，因此所有对象都可以覆盖它以返回描述对象的字符串）。
The output is also sent to the Apple System Log (ASL), which is Apple's version of syslogd. This data can be read by other applications using a C API, or by a OS X user using the application “Console”.
输出也会发送到Apple系统日志（ASL），这是Apple的syslogd版本。其他应用程序可以使用C API或使用应用程序“Console”的OS X用户读取此数据。

#3

From a developer point of view, the biggest difference is that NSLog supports Objective-C object types via the %@ format. NSLog also writes to stderr, while printf writes to stdout.

从开发人员的角度来看，最大的区别是NSLog通过％@格式支持Objective-C对象类型。 NSLog也写入stderr，而printf写入stdout。

#4

I see two main differences between NSLog and printf:

我看到NSLog和printf之间有两个主要区别：

NSLog supports NSString objects through the %@ extension;

NSLog通过％@扩展支持NSString对象;
furthermore, NSLog automatically adds time and process data (e.g., 2012-01-25 17:52:10.479 process[906:707])

此外，NSLog自动添加时间和过程数据（例如，2012-01-25 17：52：10.479过程[906：707]）

#1

printf() is a C standard library function, accepting a C string constant (const char *) as its format argument. printf() writes to stdout.

printf（）是一个C标准库函数，接受一个C字符串常量（const char *）作为其格式参数。 printf（）写入stdout。
NSLog() is a Foundation function, accepting a constant NSString as format, and has an extended format specifier set (for example, printf() does't print objects specified by %@, NSLog() does). NSLog() also prints the process name and date before it prints the actual format and writes to sdterr.

NSLog（）是一个Foundation函数，接受一个常量NSString作为格式，并具有一个扩展格式说明符集（例如，printf（）不打印由％@，NSLog（）指定的对象）。 NSLog（）还会在打印实际格式之前打印进程名称和日期，并写入sdterr。