@@ -11,17 +11,19 @@ For details about the differences between musl and glibc, see [Functional differ
C11 is implemented by [libc, libm, and libdl](https://en.cppreference.com/w/c/header).
libc: provides thread-related interfaces and a majority of standard interfaces.
-libc: provides thread-related interfaces and a majority of standard interfaces.
libm: provides mathematical library interfaces. Currently, OpenHarmony provides a link to libm, and the interfaces are defined in libc.
libdl: provides dynamic linker interfaces such as dlopen. Currently, OpenHarmony provides a link to libdl, and the interfaces are defined in libc.
- libm: provides mathematical library interfaces. Currently, OpenHarmony provides a link to libm, and the interfaces are defined in libc.
- libdl: provides dynamic linker interfaces such as dlopen. Currently, OpenHarmony provides a link to libdl, and the interfaces are defined in libc.
## musl Version
1.2.0
From OpenHarmony 4.0, musl 1.2.3 is supported.
OpenHarmony 4.0 supports musl 1.2.3.
## Supported Capabilities
OpenHarmony provides header files and library interfaces that are compatible (not fully compatible) with C99, C11, and POSIX, and supports Armv7-A, Arm64, and x86_64 architectures.
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@@ -35,32 +37,36 @@ To better adapt to the basic features of OpenHarmony devices, such as high perfo
4.**dlopen()** can directly load uncompressed files in a .zip package.
### Debugging Capabilities
The libc provides dynamic settings of the basic log functions (disabled by default) for developers to view internal exceptions of the libc. You can set the **param** to enable or disable the log functions, without recompiling the libc. However, you are advised not to use the log functions in official release versions because they affect the running performance.
The libc provides dynamic enabling of debug logging (disabled by default). The debug logs help you learn about exceptions of the libc. With this function, you only need to set **param**, which eliminates the need for rebuilding the libc. However, you are advised not to enable debug logging in official versions because it affects the running performance.
#### 1. musl.log
Set **musl.log.enable** to **true** to enable the **musl.log** function. To print other logs, you need to enable this function first.
Set **musl.log.enable** to **true** to enable printing of musl debug logs. You need to enable musl.log before printing other logs.
```
setparam musl.log.enable true
param set musl.log.enable true
```
#### 2. Loader log function
The loader starts applications and invokes dlopen() and dlclose() in libc. To view exceptions in the dynamic loading process, enable the loader log function.
* Enable the loader log of all applications (exercise caution when using this function).
#### 2. Loader logging
The loader starts applications and invokes **dlopen** and **dlclose** in the libc. To view exceptions during the loading process, you need to enable the loader logging function. The following describes common operations.
* Enable the loader logging for all applications. Exercise caution when enabling this function because a large number of logs will be generated.
```
param set musl.log.ld.app true
```
* Enable the loader log of the specified application. {app_name} specifies the target application.
* Enable the loader logging for an application specified by {app_name}.
```
param set musl.log.ld.all false
param set musl.log.ld.app.{app_name} true
```
* Enable the loader log of all applications except the specified application.
* Enable the loader logging for all applications except the specified application.
```
param set musl.log.ld.all true
param set musl.log.ld.app.{app_name} false
```
## Interfaces Not Supported by musl
[libc Symbols Not Exported](musl-peculiar-symbol.md)
[libc Symbols That May Fail to Call Due to Permission Control](musl-permission-control-symbol.md)
[Native API Symbols Not Exported](musl-peculiar-symbol.md)
[Native API Symbols That May Fail to Call Due to Permission Control](musl-permission-control-symbol.md)
